The present invention concerns firstly a method for producing and accelerating electrons and ions under application of a voltage, whereby electrodes are proposed which, under the influence of a voltage, supply electrons, and a gas being proposed which, under low pressure, supplies electrons and ions. It is known in the art to produce electron flows in a vacuum by means of thermionic emission or by point discharges, and to consequently accelerate in a corresponding voltage field. The current densities which are thereby obtainable are insufficient. In the prior art, electrons which were produced in a vacuum have been deposited through a thin foil into a chamber in which is located a gas which is under low pressure. Eventhough it is possible to thus obtain in this low-pressure area electron flows having a high current density, however, the amount of instruments required is very high and the effect is unsatisfactory.